When drying one's hair with a hair dryer, the force of the airstream sometimes causes the hair to mat; and the concentrated airstream overheats the area of impingement. When this occurs, the user often keeps the dryer in constant, somewhat oscillatory, motion to spread the airstream and agitate the hair.
Prior art attempts to solve this problem have involved a periodic blocking of the air, reducing the volumetric flow rate. For example, Lee U.S. Pat. No. 4,132,360 uses a continuously rotating blocking blade to cause pulsations. Levy et al. U.S. Pat. No. 4,019,260 a vertically mounted flexible sheet is mounted in the air stream which, in effect, flaps in the breeze and, so, partially blocks and pulses the air. Another patent, Tomaro U.S. Pat. No. 4,295,283, includes a freely-rotating fan blade in the air stream to diffuse the flow of air. The prior art does not appear to orbit the airstream, and, so, if desired, this must be done by the user.